Section 4 | Length Standards Section




The Length Standards Section of the National Metrology Laboratory of the Philippines (NML) is capable of calibrating rectangular gauge blocks ranging from 0.5 mm to 100 mm. The laboratory adopted the ISO 3650:1998 second edition as reference procedure for the determination of gauge block length by mechanical comparison using Grade K reference gauge blocks at an ambient temperature of (20 ± 0.5) ˚C.

Calibration Method

The calibration of gauge block applies the comparative measurement method, in which the gauge block to be calibrated is compared with a reference gauge block whose deviation in central length is shown on the calibration certificate supplied. (Section 8.4 of ISO 3650:1998)

Calibration Procedure

Two gauge blocks (reference/standard and calibration item) are positioned side by side on the roller table of the mechanical comparator. The length of each gauge blocks can be measured by determining the perpendicular distance at the central point of measuring face to the roller plate in which another measuring face is wrung.

Equipment and Standards


  • Michael Jason A. Solis – Section Head
  • Gerryboy C. Garinggan
  • Jessie G. Yap